Apparatus for heating test tubes



May 31, 1938. CAR. MADDEN APPARATUS FOR HEATING TEST TUBES Filed June 30, 1936 WIIIIIII'IJ 1-: E III/III; IIIIIIIII/IIIIII III" Clyda R. fiddle/L I flaw;

Patented May 31, 1938 UNITED STATES PATENT OFFICE APPARATUS FOR HEATING TEST TUBES Clyde R. Madden, Charleston, W. Va.

Application June 30, 1936, Serial No. 88,162

16 Claims.

This invention relates to devices for effecting analyses of liquids and, more particularly, is intended to provide an apparatus for heating, in a predetermined manner and to a predetermined degree, a plurality of containers such as test tubes.

It is an object of the invention to provide a heating device for use in the analysis of fluids such as urine, which is so constructed that a large number of separate fluid samples may be tested simultaneously.

A further object is to provide a heating apparatus which is particularly adapted for use in making urine analyses and which includes two heatelements which may be separately energized to facilitate the making of separate analyses for different constitutents, such as sugar and albumin. In accordance with the invention, these heating elements are so arranged with respect to the means for supporting the containers for the separate samples, that different parts of the containers may be heated at different times and in making different types of analyses. Further in accordance with the invention, there are provided means for controlling and varying the heating effect of the various heating elements, whereby the degree to which the samples are heated may be controlled as desired.

Other objects and features of novelty will be apparent from the following description and the annexed drawing, it being expressly understood, however, that the invention is not limited in any way by such description and drawing, or otherwise than by the appended claims.

35 Referring to the drawing, in which similar reference numerals refer to like parts,

Fig. 1 is a perspective view showing an apparatus according to the invention;

Fig. 2 is a cross-sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged view showing the container supporting and heating elements of the apparatus illustrated in Fig. 2, and

Fig. 4; is a circuit diagram showing the con- 5 nections for energizing the heating elements.

The present invention provides an apparatus fer effecting the heating, in a selected manner and to a predetermined degree, of one or more containers in which may be placed samples of a liauid, such as urine, for the purpose of effecting analyses of such liquids, which analyses require the application of heat to the liquid samples. An apparatus according to the invention is illustrated in the drawing and, referring thereto, it 55 will be seen that the same comprises a base I.

which is preferably a fiat member, the same being supported by legs or supports 2, 3, 4 and 5, the supports 4 and 5 being preferably arranged adjacent each other near the center of the length of the base I, as illustrated, for a purpose which will appear hereinafter.

Arranged on the upper surface of the base I means for supporting thereon one or more c'J-ntainerS; such as the test tubes 6, of which a plurality are shown in Fig. 1. Such supporting means comprise an elongated wall-like supportmember I which is arranged along the length of the base I and which extends above the upper face thereof a short distance. A second supportmember 8 is provided and comprises a flat plate-like member which lies in face to face abutment with the upper surface of base I. The supporting member 8 is of such dimensions and kness that along its longitudinal length it presents an edge 9 which is parallel to the support I and substantially coextensive in length therewith. The thickness of the supporting device 8 is preferably considerably less than the height of support 1, and the support I is spaced from the edge portion 9 of support 8 a sufficient distance to permit a container such as a test tube to be supported in inclined position by the two, the bottom of the test tube resting on the upper surface of the base I and abutting the edge portion 9 of the support 8 and the upper or intermediate portion of the test tube being supported by the upper surface of the wall-like support 1. As is illustrated, the upper surface of the support 1 may be inclined downwardly toward the lower portion of the edge portion 9 of the support 8 in order to provide a secure and shaped support for the inclined tubes 6. It will e apparent that the dimensions and configuration of the support 8 form no part of my real invention, as obviously this support may be of any desired thickness or breadth.

Means are provided for heating the test tubes which are supported in inclined position by the supports 1 and 8, and such means comprise two heating elements which are arranged to supply heat to the tubes. One of these heating elements, which is denoted by numeral I0 is arranged within. a groove which is formed in the upper surface of the wall-like support 1 and which extends throughout the longitudinal length thereof. The second heating element, which is designated by immeral II, is disposed within a groove in the upper surface of the base I and which extends parallel to and adjacent the edge portion 9 of the support 8. It will be apparent that when a test tube is supported in inclined position by the supports l and 8, as illustrated, the lower portion thereof will substantially abut the lower heating element ll, while the upper or intermediate portion thereof will abut the upper heating element Iii.

Means are provided by the invention for selectively energizing the heating elements Ill and i! so that one or the other of these may be operated to heat the tubes 6 in a manner and for a purpose to be described hereinafter. Such selective energizing means comprises the double-pole, double-throw switch device 20 which may, if desired, be arranged and supported on the upper surface of the base I. As clearly illustrated in Figs. 1 and 1, the center terminals 2i and 22 of the switch are respectively connected to one terminal of a source of electric energy by lead 33 and by lead 34 to one terminal of a variable resistance device 23 which comprises two resistance coils which are bridged by a sliding connection it. As illustrated in the drawing, the resistance coils 23 may be mounted on the supporting members 4 and 5 and the movable connecting tap It may be slidably mounted on a shaft 15 and may have connected thereto a handle I! by which it may be operated to any desired position along the resistance coils. The upper heating element iii is connected across two of the switch contacts 25 by leads 26, 21, while the lower heating element ii is connected across a second pair of switch contacts 28, 29 by leads 30, 3|. The second terminal of the source of electric energy is connected by lead 3?. to the second terminal of the variable resistance element.

It will be apparent that when switch device 2!] is operated into engagement with contacts 24, 25, a circuit will be completed from the source of electric energy through lead 33, the switch arm to contact 24, lead 25, heating element it, lead 2?, the switch arm to terminal 22, lead 34, the variable resistance member, and lead 32 to the second terminal of the source of energy. The completion of this circuit will cause heating element iii to be energized to a degree which may be regulated by movement of the variable tap connection it to put more or less of resistance 225 in circuit with the heating element. If it is desired to energize lower heating element H, the switch device as is operated into engagement with contacts 28 and 29. A circuit will thereby be set up which will cause current to flow from the source of energy through lead 33, the switch arm to terminal 28, lead 38, heating element H, lead 3!, the second switch arm to terminal 22, lead 34, the variable resistance element, and lead 32 to the second terminal of the source of energy. This circuit will cause heating element H to be energized and the degree of energization may be controlled, as before, by proper operation of the variable resistance device.

In the operation of the apparatus described, each of the test tubes 5 may have placed therein a sample of a fluid such as urine and may be placed in inclined position with their lower ends supported by the edge portion 9 of the support 8 and with their intermediate or upper portions supported by the inclined upper face of the support i. As is well known in making analyses of urine, the first test to be made is for albumin. This test requires the application of heat to the sample under analysis and this is effected, by the apparatus according to the invention, by energization of the upper heating element H], which may be effected by proper operation of the switch 20. It

will be apparent that, due to the construction of the apparatus according to the invention, a large number of separate samples may be subjected to this test simultaneously. It is also noted that in making this test, a fairly large sample is required and when this is placed in the test tube the level of liquid therein will be sufficiently high to ex tend above the upper heating element Accordingly, this heating element may be operated without endangering the test tube, which would be done if the liquid were not as high as the upper heating element 50. The second test to made in the usual analysis of urine is for sugar and in making this test a large part of the sample is removed from the test tube and small quantities of certain ingredients are added to the remaining fluid. The liquid level in the test tube is now quite low and, after replacement of the tubes upon the supports, the lower heating element 5 i is now operated to heat the small amount of liquid in the test tube. It is apparent that operation of the upper heating element iE! when there is only a small amount of liquid therein would injure the test tubes and for this reason the lower heating element may be advantageously operated.

While I have described and illustrated only a single embodiment of my invention, which contains various structural features which are not necessarily a part of the invention, it will be apparent that my invention is not limited to the particular forms and features disclosed. On the contrary, various modifications of and improvements in the device disclosed may be practiced without departing in any way from the spirit or scope of the invention, for the limits of which reference must be had to the appended claims.

What is claimed is:

1. A heating apparatus comprising a horizontal base, means for supporting a plurality of containers in inclined positions above said base com.- prising spaced. parallel elongated supporting devices mounted directly on said base, one of said supporting devices having an upper supporting surface which is disposed above said base and above the supporting surface of the other of said devices, said supporting devices providing two parallel horizontally and vertically spaced sup porting surfaces whereon a plurality of containers may be supported in inclined positions, a heating 1 element arranged adjacent the supporting surface of each of said supporting devices, and means for energizing said heating elements.

2. An apparatus for heating a plurality of containers, comprising a base, an elongated supporting device extending upwardly from said base and having a heating element supported adjacent the upper surface thereof and disposed substantially above said base, a second supporting device disposed on said base and being spaced from and parallel to said first supporting device, and a second heating element arranged adjacent to said second supporting device and lying substantially in the plane of the upper surface of said base.

3. An apparatus for heating a plurality of containers, comprising a base, an elongated supporting device arranged on said base and having an upper surface spaced substantially above said base, a heating element arranged adjacent the upper surface of said device, an elongated member arranged on said base and having an edge portion providing an abutment which is parallel to and; spaced from said supporting device, and a second heating element arranged substantially in the plane of the base and being parallel to and adjacent the said abutment.

4:. An apparatus for heating a plurality of containers, comprising a base, an elongated supporting device arranged on said base, a second elongated supporting device arranged on said base and being parallel to and spaced from said first supporting device, the upper surface of said first supporting device being inclined toward said second supporting device for the accommodation in an inclined position of a plurality of containers the lower ends of which abut the lower portion of said second supporting device, an elongated heating element arranged adjacent the upper surface of said first supporting device and a second elongated heating element arranged adjacent the intersection of said second supporting device and said base.

5. An apparatus for heating a plurality of containers, comprising a base, an elongated vertical support arranged on said base, a second elongated support arranged on said base and having an edge portion which is substantially parallel to and spaced from said first support, the upper surface of said first support having a groove therein extending longitudinally thereof, the upper surface of said base having a groove formed therein which is parallel to and adjacent said edge portion, and a heating element disposed in each of said grooves.

6. An apparatus for heating a plurality of containers, comprising a base, an elongated vertical support arranged on said base, a second elongated support having a vertical edge portion which is substantially parallel to and spaced from said first support, said first support being provided with an upper surface which is inclined toward the intersection of said second support with said base and in which there is formed a groove extending longitudinally of the support, said base being provided with a groove which is parallel and adjacent to said edge portion, and a heating element disposed in each of said grooves.

7. An apparatus for heating a plurality of containers, comprising a. base, an elongated support on said base having an upper surface raised above said base, a heating element extending along the upper surface of said support, a second heating element arranged substantially in the plane of said base and being spaced from and parallel to said support, and an elongated abutment arranged parallel to and adjacent said second heating element.

8. An apparatus for heating a plurality of containers, comprising a base, an elongated support on said base and having an upper surface raised above said base, a heating element extending along the upper surface of said support, a second heating element arranged substantially in the plane of said base and being spaced from and parallel to said support, an elongated abutment arranged parallel to and adjacent said second heating element, and means for selectively energizing said heating elements.

9. An apparatus for heating a plurality of containers, comprising a base, an elongated heating element supported above the upper surface of said base, a second elongated heating element arranged substantially in the plane of said base and being parallel to and spaced laterally from said first heating element, a variable resistance device, and means for selectively placing either one or the other of said heating elements in circuit with said resistance device and with a source of electric energy.

10. An apparatus for heating a plurality of test tubes comprising a base, an elongated support arranged on said base and having an inclined upper surface on which the interme diate portions of a plurality of test tubes may be supported in inclined position, an elongated abutment arranged on said base and being parallel to said support and substantially spaced therefrom and providing an abutment for the lower ends of a plurality of test tubes, a heating element arranged adjacent the inclined upper surface of said support, a second heating element arranged adjacent said abutment, and means for energizing said heating elements.

11. An apparatus for heating a plurality of test tubes comprising a base, an elongated support arranged on said base and having an inclined upper surface for supporting the intermediate or upper portions of a plurality of test tubes in inclined position, a separate elongated abutment arranged on said base and being parallel to and spaced from said support and providing an abutment against which the bottoms of said test tubes may be rested, an elongated heating element disposed adjacent the upper surface of said support for heating the upper portions of test tubes which may be supported by said support, and a second elongated heating element arranged adjacent said abutment for heating the lower portions of test tubes supported thereby.

12. An apparatus for heating a plurality of containers, comprising a base, an elongated heating element supported above the upper surface of said base, a second elongated heating element arranged adjacent the plane of said base and being parallel to and spaced laterally from. said first heating element, a variable resistance device, and manually operable switch means for selectively placing either one or the other of said heating elements in circuit with said resistance device and with a source of electric energy.

13. An apparatus for heating a plurality of containers, comprising a base, an elongated. heating element supported above the upper surface of said base, a second elongated heating element arranged adjacent the plane of said base and being parallel to spaced laterally from said first heating element, a variable resistance device, and manually operable switch means supported by said base for selectively placing either one or the other of said heating elements in circuit with said resistance device and with a source of electric energy.

14. An apparatus for heating a plurality of containers, comprising a base, an elongated heating element supported above the upper surface of said base, a second elongated heating element arranged substantially in the plane of said base and being parallel to and spaced laterally from said first heating element, a variable resistance device, and manually operable switch means mounted on the upper surface of said base for selectively placing either one or the other of said heating elements circuit with said resistance device and with a source of electric energy.

15. An apparatus for heating a plurality of containers, comprising a base, an elongated heating element supported above the upper surface of said base, a second elongated heating element arranged adjacent the plane of said base and being parallel to and spaced laterally from said first heating element, a manually operable variable resistance device carried by said base and operable to selectively place either one or the other of said heating elements in circuit with said resistance device and with a source of electric energy.

16. An apparatus for heating a plurality of containers, comprising a base, an elongated heatj ing element supported above the upper surface of said base, a second elongated heating element arranged adjacent the plane of said base and being parallel to and spaced laterally from said first 

